Without closer look, my first guess is Grenson too, though Grenson usually doesn't write the style name inside shoes, but they might in the PS shoes. Come to think of it, Green doesn't write style name in the shoes either. Lobb does, so does Trickers --- but those are definitely not Lobb or Trickers. The other possibility is Alfred Sargent, as they make some of the PS shoes (Jodhpur boots this season), but it doesn't look like a Sargent last either. So my best guess is Grenson.